Is that a "Reverse Polish Notation" (RPN) calculator? I see an Enter button and no equals sign, so I'm guessing it is. You say it's a TI-30, but those were made back in the mid-70's.

Anyways, to use RPN you always start deep in the formula and work your way toward the outside, as opposed tp left-to-right as on a "normal" calculator. So for

start with the square root, then multiply by 5 then do the 2 pi calculation, then subtract that result from the first, then "exponentiate" the result. The sequence is:

2 2nd x^2

5 X

2 Enter

Pi X

Minus

2nd LN